Our site is updated on a daily basis, but on yahoo it still shows our old title and description from 3 years ago. Now we are top ranked in alot of our keywords, but it would be a lot better if we were able to get these updated to our new tags. I have tried re-submitting our site and it never gets updated. Our old tags show in our directory listings too.
If a site is listed in the Yahoo directory or in Dmoz, Yahoo's crawlers use that as the description for the site,. If you want to go around this, you'd have to get your site removed from the 2 directories, but that might make your site drop in rankings as those are two valuable links.